Circuit Diagram

PCM_TELEMETRY_MULTIPLEXER

Published:2009/7/19 22:18:00 Author:Jessie

Permits gate-switching transistors Q1-Q2 to double in ring counter and control sequencing. Uses four-diode bridge for each gate, with single transformer-coupled looting voltage source switched to each gate in succession by two. transistor switching gate.-R. C. Onstad, Solid-State 30-Channel Multiplexor Designed for Minimum Components, Electronics, 34:40, p 77-79.   (View)

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CODE_PRACTICE_OSCILLATOR_I

Published:2009/7/10 2:49:00 Author:May

Q1, a unijunction transistor, generates a sawtooth of about 1.5 to 2 kHz, depending on C1 and R1. Q2 acts as a speaker driver. A 9-V battery is used, and the keying is done by keying the supply line.   (View)

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FET_PHASE_SHIFT_OSCILLATOR

Published:2009/7/19 22:18:00 Author:Jessie

Frequency of four-mesh phase-shift oscillator can be varied several cycles around 10 cps, using 2.5-meg pot. Attenuation of four-mesh feedback network is 18.36.-L. J. Sevin, Jr., Field-Effect Transistors, McGraw-Hill, N.Y., 1965, p 111.   (View)

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10_bit_A_D_converter_interface_with_an_8_bit_bus_such_as_in_the_8080_control_structure

Published:2009/7/19 22:17:00 Author:Jessie

10-bit A/D converter interface with an 8-bit bus such as in the 8080 control structure (courtesy Analog Devices, Inc.).   (View)

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50_to_150_MHz_OSCILLATOR

Published:2009/7/10 2:48:00 Author:May

  (View)

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FEEDBACK_OSCILLATOR

Published:2009/7/19 22:17:00 Author:Jessie

C1 provides positive feedback between amplifier V2 and cathode follower V1, causing oscillation at frequency and amplitude at which loop gain is unity. Twin-T network in negative feed-back loop maintains pure sine wave, free of harmonics. Variable-gain negative-feedback amplifier V3-V4 stabilizes frequency and amplitude at prescribed values.-Oscillator Patent is Granted, Electronics, 31;37, p 108.   (View)

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STABLE_VFO

Published:2009/7/10 2:45:00 Author:May

This VFO circuit covers from 2.13 to 2.58 MHz and is intended for use with an external mixer to heterodyne the signal to desired frequencies. Coil data is shown in the parts list. Two power outputlevels are available-a few hundred mW (0 to + 3 dbm) from Q3. Q4 is a class A amplifier for boosting the power to +22 dbm for driving a high-level mixer. The VFO can be operated on other frequencies, with suitable component charges (see the table).   (View)

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±65V_TRACKING_AT_1A

Published:2009/7/19 22:16:00 Author:Jessie

Circuit uses two LM143 high-voltage opamps in combination with zener reference and discrete power-transistor pass elements.Q1 is transistor used as stable 6.5-V zener voltage reference. Opamp A1 amplifies reference voltage from 1 to about 10 times for application through R10 to Darlington-connected transistors Q2 and Q3. Feedback resistor R5 is made variable so positive output voltage can be varied from 6.5 V to about 65 V. This output is applied to unity-gain inverting power opamp A2 to generate negative output voltage. Q2-Q5 should be on common Ther-malloy 6006B or equivalent fleatsink. Supply includes short-circuit protection. Maximum shorted load current is about 1.25 A.- Linear Applications, Vol. 2, National Semiconductor, Santa Clara, CA, 1976, AN-127, p 8-9.   (View)

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ELECTROLYTIC_CAPACITOR_REFORMING_CIRCUIT

Published:2009/7/10 2:45:00 Author:May

Sometimes electrolytic capacitors that are stored for some time will exhibit high leakage currents.Before placing these in service, the capacitors might need to be reformed. This power supply can be used for reforming. Adjust R4 for the capacitor's rated voltage and set S2 in position 1. When M1 indicates the rated voltage, reforming is complete. For large capacitors, use position 2, and then position 3 after reform-ing starts. T1 can be any transformer with a rating of 12 to 24 Vac at about 1A.   (View)

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Cold_junction_compensation_for_type_K_thermocouple

Published:2009/7/19 22:16:00 Author:Jessie

This circuit shows an AD590 that is connected to compensate a type-K thermocouple. The reference junctions should be in close thermal contact with the AD590 case. V+ must be at least 4 V and ICL8069 current should be set at 1 to 2 mA. Calibration does not require shorting or removal of the thermocouple. Set R1 for V2= 10.98 mV. If very precise measurements are needed, adjust R2 to the exact Seebeck coefficient for the thermocouple used (measured or from table), then note V1 and set R1 to buck out this voltage (that is, set V2 to equal V1). For other thermocouple types, adjust values to the appropriate Seebeck coefficient.   (View)

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150_to_30_000_kHz_OSCILLATOR

Published:2009/7/10 2:45:00 Author:May

C1 capacitor in series with the crystal may be used to adjust the output frequency of the oscillator. The value can range between 20 pF and 0.01 μF, or it can be a trimmer capacitor. X values are approximate and can vary for most circuits and frequencies; this is also true for resistance values. Adequate power supply decoupling is required; local decoupling capacitors near the oscillator are recommended.   (View)

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SATELLITE_TRANSMITTER

Published:2009/7/19 22:16:00 Author:Jessie

Novel phase modulator, based on bridged-T network, gives simple design dong with wide modulating capability. Transmitter has output of 300 mw at 108 Mc for telemetering data for up to 18 months from Van Allen radiation bell.-A. J. Fisher, W. R. Talbert, and W. R. Chittenden, Telemetry Transmitter for Radiation Satellite, Electronics, 33:19, p 68-69.   (View)

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STATIC_DETECTOR

Published:2009/7/10 2:43:00 Author:May

This circuit detects the presence of electrostatic fields by using an FET to alter the flash rate of two LEDs. The FET is installed in the timing circuit and causes a change in the flash rate of the two LEDs.   (View)

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CASCADE_TUNNEL_DIODE

Published:2009/7/19 22:16:00 Author:Jessie

Voltage drops across resistors R2 serve as individual voltage sources in series for cascaded diodes that give three times sine-wave output voltage of single relaxation oscillator circuit.-Wen-Hsiung Ko, Designing Tunnel Diode Oscillators, Electronics, 34:6, p 68-72.   (View)

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1_to_4_MHz_CMOS_OSCILLATOR

Published:2009/7/10 2:42:00 Author:May

Notes： 1 1 MΩ＜R1＜5 MΩ2 Select R2 and C2 to prevent spunous frequency．3 ICs are 74C04 or equiwlent   (View)

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LOW_ENERGY_PARTICLE_DETECTOR

Published:2009/7/19 22:16:00 Author:Jessie

Change in conductivity of single-crystal photocell under irradiation is converted to pulse-code modulation by neon glow-tube relaxation oscillator whose Firing rate is determined by charging of C1 through photocell. Saturating bootstrap amplifier Q2 inverts and shapes pulses to drive accumulation register-J. W. Freeman, Energy Detector for Satellites, Electronics, 35:4, p 42-43.   (View)

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FET_VOLTAGE_CONTROLLED_OSCILLATOR

Published:2009/7/19 22:15:00 Author:Jessie

Produces excellent sine-wave output with good linearity over frequency range of 1,500 to 2,500 cps, for control voltage of 0to 7 V d-c. Circuit is resistance-controlled three-section phase-shift oscillator.-R. Selleck, Voltage-Controlled Oscillators, EEE, 13:3, p 47.   (View)

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PHASOR_SOUND_GENERATOR

Published:2009/7/10 2:42:00 Author:May

The 4011B astable is gated by S1 to produce 4-ms pulses at 70－ms intervals. Each pulse charges C2 via D2 producing a high tone that decays slowly as C2 discharges through R5.The process repeats for each pulse   (View)

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FEEDBACK_LOOP_STABILIZES_A_F_OSCILLATOR_AMPLIFIER

Published:2009/7/19 22:14:00 Author:Jessie

Wien bridge determines frequency of oscillator, which is combined with amplifier stages to give single oscillator stage having suffident output power to drive load directly. Thermistor R2 and resistor R3 provide negative feedback path around amplifier and oscillator, to make oscillator gain and frequency independent of load variations.-R. G. Fulks, Novel Feedback loop Stabilizes Audio Oscillator, Electronics, 36:5, p 42-43.   (View)

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lO_to_80_MHz_OSCILLATOR

Published:2009/7/10 2:41:00 Author:May

Notes:1. Y1 is AT cut, fundamental, or overtone crystal.2. Tune L1 and C2 to operating frequency.   (View)

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